Seamless hydraulic tube materials and standards

Seamless hydraulic tube materials and standards

Hydraulic steel pipes are basically divided into fluid pipes and oil steel barrels used in hydraulic systems, also called honing pipes, while cold-drawn or cold-rolled precision seamless steel pipes also include hydraulic steel pipes. The material is generally steel.

The domestic standard for fluid pipes on hydraulic systems that is close to the national standard is GB3639-83. Introduction to hydraulic steel pipes: cold-drawn or cold-rolled precision seamless steel pipes for hydraulic equipment with high dimensional accuracy and good surface finish. Precision seamless steel pipes are used to manufacture mechanical structures or hydraulic equipment. Precision steel pipes are high-precision seamless steel pipes that are cold drawn or cold rolled. Precision steel pipes are mainly used to produce pneumatic or hydraulic products because they have no oxide layer on the inner and outer walls, can withstand high pressure without leakage, have high precision, high smoothness, no deformation in cold bending, no cracks in flaring and flattening, etc.

In the standard it is DIN2391-1. The raw materials of the hydraulic steel pipe have been finely drawn, non-oxidized and brightly heat treated (NBK state), non-destructive testing, the inner hole of the steel pipe has been high-pressure rinsed and pickled, the inner and outer walls of the steel pipe are treated with anti-rust oil, and both ends are capped for dust prevention. . The produced steel pipes have high precision and good smoothness. There is no oxide layer on the inner and outer walls of the steel pipes. The steel pipes can withstand the high pressure of liquid flowing through them. The steel pipes are cold-bent without deformation and can be expanded and flattened without cracks. Mechanical properties: Can be bent at any angle without deformation. Mainly used as steel pipes in the oil circuit of hydraulic systems, also called hard piping in hydraulic systems. Precision steel pipes for automobiles. The specifications are generally outer diameter (D) Φ4mm-76mm and wall thickness (S) 0.5mm-6.0mm. The length is fixed length 6 meters (except custom-made), and the delivery status is NBK (normalized), GBK (annealed), BKS (stress relief annealed). The main materials used are ST35, ST37.4 (10#), ST45 (20#), ST55 (35#), ST52 (16Mn), etc., which can meet the requirements for steel pipes with high precision, high smoothness, tensile strength, and high mechanical properties. client.

Introduction to hydraulic steel pipes based on European standard EN10305-4:2003: The precision hydraulic steel pipes produced are precision cold-drawn seamless pipes, which are made through anaerobic tempering treatment to eliminate surface and internal stress and then undergo phosphating and anti-rust treatment. The product has high dimensional accuracy and good ductility, and is easy to be processed and bent into various required shapes without the pipe section shrinking or flattening; the pipe has high surface precision, moderate surface hardness after anaerobic tempering treatment, and is easy to connect with ferrules. The inner hole After the surface is phosphated and rust-proofed, it can be installed directly without pickling and rust removal.

Honed pipe: Cold-rolled precision seamless steel pipe is made of finished seamless steel pipe or raw seamless pipe, which is pickled, phosphated, and saponified, and then rolled by a cold-rolled pipe machine to form a hydraulic steel pipe. The extremely high precision of hydraulic steel pipes can generally be controlled within the range of 0.02-0.05MM. The standard is: GB3639-83, the allowable deviation of the inner diameter is 0.03mm, the inner surface roughness: Ra 0.2~0.8μm, and the straight line of hydraulic steel pipes Degree: 0.3~1.5mm/m, specially used for oil steel barrel diameter.

Standard for seamless hydraulic tube

There are many standards for seamless hydraulic steel pipes at home and abroad. The following are commonly used:

1. GB/T 17396-2009: Chinese national standard, applicable to oil pipes in general hydraulic systems;
2. DIN 2391-1: German standard, applicable to oil pipes in precision hydraulic systems;
3. ASTM A519: American standard, applicable to mechanical structures, automobile manufacturing and other fields, and can also be used in hydraulic systems;
4. JIS G3445: Japanese standard, applicable to oil pipes in mechanical structures.

Selection factors of seamless hydraulic steel pipes

The following factors should be considered when selecting a suitable seamless steel pipe:

1. Material: Select appropriate materials according to the medium in the hydraulic system, generally including carbon steel, alloy steel, stainless steel, etc.;
2. Size: Select appropriate pipe diameter and wall thickness according to the load in the hydraulic system;
3. Working temperature and pressure: Select appropriate materials and sizes according to the working conditions in the hydraulic system;
4. Port connector: Select the appropriate port type and size according to the connector in the hydraulic system to ensure the sealing of the connection;
5. Surface treatment: Select appropriate surface treatment methods according to the working environment in the hydraulic system, such as phosphating, galvanizing, spray painting, etc.

Conclusion

Seamless hydraulic steel pipes is an indispensable pipe material in the hydraulic system. Its selection should be considered based on the working conditions, medium, load and other factors in the hydraulic system. The correct selection of suitable seamless steel pipes can improve the stability and reliability of the hydraulic system and reduce the failure rate and maintenance costs.